It has been demanded to perform more versatile communication using communication terminals used by individuals. In such situations, transmission of information from a server device side of a service provider to those communication terminals while the transmission is controlled by a server device side, so called, means of a push notification, has been required. Regarding the push notification, instead of the server device sending a response to a request from the communication terminal side, information is transmitted from the server device side to the communication terminal without a trigger from the communication terminal side. One of protocols used for the above purpose is XMPP (extensible messaging and presence protocol). Non-Patent Document 1 discloses XMPP and also provision for applying XMPP to a push communication. The XMPP is protocol based on XML (extensible markup language), and is adopted as the standard for instant messaging.